From sand mining to flood prevention: 5 facts on reducing flood risk in Lagos

  • 2022•11•23     Bonn, Germany

    © Sebastian Barros

    The residents of Lagos, one of Africa’s biggest cities, are faced with increasingly severe annual flooding of their city, which is threatened by sea level rise and sinking at a rate of up to ~87 mm per year. In 2021, floods again submerged vehicles and houses, displacing thousands from their homes. By 2050, climate change increasing precipitation rates and the risks of subsequent flooding will be twice as high as today and sea level rise will result in half of the city at risk of being underwater by 2100 if nothing is done.

    1. The hidden industry of sand mining creates a deadly threat

      Sand is second only to water as the world’s most-used natural resource and is a crucial component for multiple economic sectors, including construction. Sand mined at Lagos’ shorelines to supply a construction boom in the area leads to eroding coastlines and the destruction of coastal ecosystems, which are critical for protecting the inhabitants from storms and rising seas.

    2. Social inequality makes matters worse

      Lagos is rapidly expanding as the population grows and people flock from rural areas towards urban centres in hopes of better economic opportunities. As grand building projects spring up for those that can afford them, the vulnerable people in the city are continually pushed to the margins and into harm’s way by development and disasters.

    3. Use innovative materials to curb demand pressure

      Luckily, coastal sand mining is not the only way to obtain materials to construct new buildings. Using alternative building materials, such as timber, can reduce the demand for sand and provide a renewable source for building materials. Additionally, recycling old building materials through a practice of “urban mining” means more sustainable consumption of resources and a reduced demand pressure to mine raw materials.

    4. Work together for a better future

      Addressing flooding in Lagos should also involve tackling improper waste disposal through participatory waste management. Bringing regional and municipal governments together with community groups and residents to co-develop waste-management plants is key for their success. Additionally, Lagos should consider including the informal waste economy, where people often take wheelbarrows to collect trash, in formal municipal waste management systems, especially considering their role in reaching interior and flood-prone areas.

    5. Comprehensive risk management strategies are the way forward

      There are many other possible solutions, such as improved flood forecasting, “smart” urban governance or green infrastructure, which would also be necessary for a more holistic risk management strategy. This solution package approach represents the idea that none of these measures are sufficient if they are implemented in isolation, and that the problem can only be truly addressed when solutions are implemented collectively.